Re: [LTP] lib: add module is loaded check

[linuxtestproject.agent@gmail.com]

Hi Li,

On Thu, 8 Oct 2026, Li Wang wrote:
> lib: add module is loaded check

--- [PATCH 1/4] ---

> diff --git a/include/tst_module.h b/include/tst_module.h
> +bool tst_module_is_loaded(const char *mod_name);

Low: Add kernel-doc for this new public API, including mod_name and the
return value. Document normalization, built-in modules, and the current
false return when /proc/modules cannot be read.

--- [PATCH 2/4] ---

> diff --git a/include/tst_kconfig.h b/include/tst_kconfig.h
> + * Called from do_test_cleanup() so that the modules are released when
> + * the test finishes, regardless of the test result.

Low: The actual caller is do_cleanup(), in the library parent process,
not do_test_cleanup(), which invokes the test's cleanup callback.
Correct the lifecycle description.

> diff --git a/lib/tst_kconfig.c b/lib/tst_kconfig.c
> +#define MAX_LOADED_MODULES 16
> +	if (loaded_module_count < MAX_LOADED_MODULES)
> +		loaded_modules[loaded_module_count++] = mod;

Medium: This commit already has 19 mappings, so a valid requirement list
with all 19 available as modules passes the config check but queues only
16, silently omitting three required loads. Size the storage from the
mapping table or allocate enough space instead of discarding entries.

>  				kconfig_module_check(&vars[i]);
> +				kconfig_module_record(vars[i].id);

Medium: kconfig_module_check() can change choice to 'n' for an uninstalled
module, but this still queues it. For CONFIG_MMU | CONFIG_CAN_RAW with
MMU=y and an uninstalled CAN_RAW=m, the expression succeeds, then loading
can-raw aborts the otherwise runnable test. Queue only configs that
remain enabled after checking, without making optional branches mandatory.

> +	for (i = 0; i < loaded_module_count; i++) {
> +		tst_res(TDEBUG, "Loading module '%s'", loaded_modules[i]);
> +		tst_modprobe(loaded_modules[i], NULL);
> +	}
> +
> +	modules_loaded = true;

High: If one modprobe succeeds and a later one aborts, modules_loaded is
still false, so the cleanup helper returns without unloading the earlier
module. Track each successful load immediately and let abort cleanup
unload that successful prefix, not unattempted entries.

> +		const char *const argv[] = { "rmmod", loaded_modules[i - 1], NULL };
> +		tst_cmd(argv, "/dev/null", "/dev/null", TST_CMD_PASS_RETVAL);

Medium: modprobe also inserts dependencies, but this removes only the
explicitly recorded names. With CONFIG_CAN=m and CONFIG_CAN_RAW=m,
loading can-raw also loads can; removing can-raw leaves the newly loaded,
unused can module behind. Track newly loaded dependencies and remove
only test-owned modules in dependency order.

--- [PATCH 3/4] ---

> The test also needs root to load the modules and to run as the
> vsock_loopback transport is not available from an unprivileged user
> namespace.
> diff --git a/testcases/cve/cve-2025-21756.c b/testcases/cve/cve-2025-21756.c
> +	.needs_root = 1,

Low: Root is needed for module insertion, but loopback VSOCK on
nonprivileged ports in the initial namespaces does not require root;
an ordinary nonroot process is not an unprivileged user namespace.
Correct the commit message and document the loading-only requirement in
the test description. Drop privileges for the reproducer after the
framework has loaded the modules.

Verdict - Needs revision

Pre-existing issue: sctphantom's description requests manual module
preloading, although its setup already loaded sctp before this series.

---
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